Mobile, accurately mechanically variable high reactive power inductor having low headroom requirements suitable for transport on a utility vehicle

ABSTRACT

A mobile, accurately mechanically variable high reactive power inductor having low headroom requirements suitable for transport on a utility vehicle such as a truck or automotive test van to a remote field location for testing large capacitative loads such as large capacitors, a group of capacitors, high voltage electrical power transmission lines, sections of transmission networks and the like. This high reactive power inductor is of the type having a magnetic core and an electrical winding magnetically coupled to the core. The core is constructed with upper and lower core segments mounted on respective upper and lower frames. A plurality of linearly telscoping jacks are positioned between the upper and lower frames to hold them positively in alignment in all positions and to vary the size of the gap between the upper and lower core segments. These jacks are constructed to maintain the upper and lower core segments in proper aligned relation irrespective of the movement or inclination of the utility vehicle so that the power inductor can be transported without special precautions to prevent damage and is immediately ready to be put into use in the field following transport to a test site.

United States Patent [191 Schutz I 1 1 Mar. 18, 1975 MOBILE, ACCURATELY MECHANICALLY VARIABLE HIGH REACTIVE POWER INDUCTOR HAVING LOW HEADROOM REQUIREMENTS SUITABLE FOR TRANSPORT ON A UTILITY VEHICLE [75] Inventor: Richard F. Schutz, Brewster, NY.

[73] Assignee: Hipotronics, Inc., Brewster, N.Y.

[22] Filed: Oct. 12, 1973 [21] App]. No.: 405,840

Primary Examiner-Thomas J. K ozma Attorney, Agent, or FirmParmelee, Johnson & Bollinger [57] ABSTRACT A mobile, accurately mechanically variable high reactive power inductor having low headroom requirements suitable for transport on a utility vehicle such as a truck or automotive test van to a remote field location for testing large capacitative loads such as large capacitors, a group of capacitors, high voltage electrical power transmission lines, sections of transmission networks and the like. This high reactive power inductor is of the type having a magnetic core and an electrical winding magnetically coupled to the core. The coreis constructed with upper and lower core segments mounted on respective upper and lower frames. A plurality of linearly telscoping jacks are positioned between the upper and lower frames to hold them positively in alignment in all positions and to vary the size of the gap between the upper and lower core segments. These jacks are constructed to maintain the upper and lower core segments in proper aligned relation irrespective of the movement or inclination of the utility vehicle so that the power inductor can be transported without special precautions to prevent damage and is immediately ready to be put into use in the field following transport to a test site.

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MOBILE, ACCURATELY MECHANICALLY VARIABLE HIGI-I REACTIVE POWER INIDUCTOR HAVING LOW HEADROOM REQUIREMENTS SUITABLE FOR TRANSPORT ON A UTILITY VEHICLE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile, mechanically adjustible high reactive power inductor for testing large capacitive loads such as large capacitors, a group of capacitors, high voltage electrical power transmission lines, sections of transmission networks, and the like. When such a high capacitive load is tested with a high reactive power inductor of the type described, the inductor is connected to the load so that its inductance can be resonated with the loads capacitance. This resonance condition causes the voltage applied to the load to be many times larger than the exciting voltage used to drive, i.e., energize, the test circuit, as is explained morefully in US. Pat. No. 3,515,986 of Stanley G. Peschel. The inductance is adjusted by changing the gap between the cores until a resonance condition between the inductor and the capacitance of the load is established. When this resonance condition is obtained,

the exciting voltage being applied to the circuit is gradually increased to a level where the capacitive load is subjected to the desired test voltage.

This resonance system reduces the actual magnitude of the exciting voltage needed to test a capacitive load. Further, the system reduces requirements for reactive power which is drawn from the electrical supply, and reduces equipment damage which may result if the test load breaks down during operation. If for example, the tested capacitive load breaks down, the resonance condition established between the capacitive load and the inductor is ended and thus the load voltage immediately drops, thereby avoiding undue damage to the load.

The resonance circuit of a high reactive power inductor of the type described below is capable of producing very high voltages. The reactive power of such an inductor is also very high. Furthermore, the attractive forces generated between the core segments are highest when the gap size is small and small variations in gap size can significantly affect the inductance pro duced. Thus it is important to be able accurately to control and vary this gap size.

It would be-desirable to be able to transport such a high reactive power inductor to a remote field location over bumpy roads and rough terrain for testing large capacitive loads found there. However, the core segments and electrical windings must be correctly aligned during transport for proper operation and to assure that the movement of the core segments will not damage the windings.

The present invention provides a supporting structure which not only permits accurate adjustment of gap size but also maintains the core segments in alignment with each other and with the electrical windings during transport and at the field test site in spite of inclination of the test vehicle when his parked at the site. Moreover the present invention provides such an inductor which has a low headroom requirement.

DESCRIPTION OF THE PRIOR ART High reactive power inductors are known in the prior art. Such inductors are disclosed in US. Pat. Nos. 3,515,986 Peschel; 3,609,6l4 Schutz and 3,703,692 Peschel. Typically high reactive power inductors have a magnetic core in the form of upper and lower, separable core segments separated by a gap, and an electrical winding magnetically coupled to the core. These inductors are generally large, having rigid supporting constructions designed to accurately, mechanically adjust the size of the gap between the upper and lower core segments.

These high reactive power inductors are generally so large and so constructed that it is impractical to attempt to transport them to remote test sites over rough terrain. They usually are supported in tall structures which are too large to be carried in a light utility vehicle, such as a light truck or test van where headroom is at a premium.

Additionally, the construction of such prior mechanically variable inductors is generally not adapted to provide core-winding alignment during transport over rough terrain. Therefore, prior art high reactive power inductors are not suitable for all testing of high capacitive loads.

The apparatus of the present invention is intended to minimize the difficulties characteristic of prior art apparatus, and to provide an advantageous mobile inductor.

SUMMARY OF THE INVENTION In a preferred embodiment to be described in detail below, the mobile, accurately mechanically adjustible high reactive power inductor of the present invention is designed for convenient transport to and use at a remote field testing location. This high reactive power inductor is of the type having a magnetic core and an electrical winding magnetically coupled to the core. This core includes an upper and a lower core segment which are separable by a gap.

This inductor further comprises a rigid lower frame upon which the lower core and the electrical winding are supported. A rigid upper frame is reciprocally mounted above the lower frame and supports the upper core segment. A plurality of linearly telescoping jacks or tube guides are mounted between the upper and lower frames for adjustibly varying the gap size between the core segments by vertically, reciprocally positioning the upper frame relative to the lower frame. These linearly telescoping jacks are constructed to rigidly maintain the alignment of the upper and lower core segments and the electrical winding irrespective of vibration and generally random vertical and horizontal motion which the inductor may experience during transport over bumpy roads and rough terrain.

A driving motor is operably coupled to the linearly telescoping jacks, or tube guides to drive them synchronously for simultaneously increasing or decreasing the total length of each jack to thus vary the gap size.

The jacks maintain relative proper alignment of the upper and lower frames and, hence, maintain coreelectrical winding alignment. Thus the high reactive power inductor of the present invention may be transported to and operated at a remove field site without disturbing alignment of the core segments and the electrical winding even though transported over rough terrain.

Since the upper and lower frames are mounted reciprocally with respect to each other the total height of the inductor of the present invention may be reduced. This arrangement eliminates the need for a tall supporting structure in order vary gap size and support the core segments. Therefore, the inductor of the present invention may be conveniently carried in a light utility vehicle having limited headroom.

Accordingly, it is an object of the present invention to provide a unique and novel mobile, accurately mechanically variable high reactive power inductor.

Other objects, aspects and advantages of the present invention will be pointed out in or will be understood from the following detailed description, when considered in conjunction with the accompanying drawings briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of an automotive test van showing high reactive power inductor of the pres ent invention mounted inside.

FIG. 2 is a front elevational view of the high reactive power inductor of the present invention illustrating the electrical windings and magnetic core segments mounted on the upper and lower supporting frames.

FIG. 3 is a side elevational view of this reactive power inductor shown on a scale enlarged from FIG. 2, as seen looking toward the left from the plane 33 in FIG. 2 illustrating the construction of the upper and lower frames and showing two of four linearly telescoping jacks or tube guides which adjustably vary the gap size between the upper and lower core segments.

FIG. 4 is a top view of this reactive power inductor on the same scale as FIG. 2 showing the driving motor and the gear and chain arrangement which synchronously drives each of the linearly telescoping jacks.

FIG. 5 illustrates one arrangement of gears suitable for coupling the driving motor to the gear and chain arrangement used to drive the linearly telescoping jacks.

FIG. 6 is a cross-sectional view of one of the linearly telescoping jacks taken through plane 66 in FIG. 2 looking toward the left showing the means of connecting it to the upper and lower frames and showing its internal construction.

FIG. 7 is an enlarged cross-sectional view of an antifriction bearing arrangement, taken through plane 77 in FIG. 2 looking toward the left, which shows how the linearly telescoping jacks may be carried in the upper frame.

Corresponding reference numerals indicate corresponding structural elements and corresponding characteristic features in each of the respective drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the mobile, high reactive power inductor 10 of the present invention which may be used to test high capacitive loads, such as high voltage power transmission lines, sections of transmission networks, large capacitors and the like mounted in an automotive test van 4. The power inductor 10 is suspended in a tank 6 that contains a transformer oil bath 8 in which the inductor 10 is emersed. The oil bath provides dielectric strength and serves to cool the inductor 10. This high reactive power inductor 10 is compact; it re quires minimal headroom and may be easily transported on a light utility vehicle such as a light truck or an automotive test van like that shown in FIG. 1.

FIGS. 2 and 3 illustrate the high reactive power inductor 10, in detail, which comprises a magnetic core which includes an upper core segment 12 and a lower core segment 14 that are separable by a gap g. The lower core segment 14 is U-shaped in front elevation with its upwardly extending legs positioned in electrical windings 16. The upper core segment 12 is inverted U shaped in front elevation with its downwardly extending legs also positioned in the electrical windings 16. These windings 16 are connected so that their inductance may be effectively resonated with the capacitive load being tested. Connection of the windings 16 may be in either series or parallel depending upon the testing conditions encountered. The windings 16 are magnetically coupled to the core segments 12 and 14. Therefore, an increase in gap size g, between the core segments, reduces the inductance of the windings l6 and a decrease in gap size g increases the inductance of the windings 16.

The lower core segments 14 and the electrical windings 16 are supported on a lower frame construction 18. This lower frame construction 18 is advantageously fabricated from rigid steel and includes two parallel channel irons 20 and 22. As shown in FIG. 3, the horizontal portion 24 of the U-shaped lower core segment 14 is clamped between the channel irons 20 and 22, the web portions 26 and 28 of which face this horizontal portion 24. A layer of insulating fiberboard 30 is positioned between channel iron web portions 26 and 28 and the outermost laminations of the lower core segment 14. A pair of V-shaped clamps 32 are positioned in each channel iron at spaced channel locations. The legs of the clamps 32 are engaged with the channel flanges and contact the channel web portions.

The clamps are also matched in pairs at opposing locations on opposing channel irons. Heavy bolts 34 interconnect these opposing clamps 32 and tightly secure the core segment 14, the insulating fiberboard layer 30, and the channel irons 20 and 22 between the opposing clamps 32. Insulating sleeves are mounted in the core segment to electrically insulate these bolts 34 from core laminations.

As shown in FIG. 3, the upper core segment 12 is suspended from an upper frame construction 36 of configuration similar to that of the lower frame construction. The horizontal portion 38 of the upper core segment 12 is mounted between opposing channel irons 40 and 42, made from rigid steel. The channel iron web portions 44 and 46, which face this horizontal portion 38 are insulated from the upper core segment 12 by fiberboard layers 52. This channel iron-insulation-core segment arrangement is tightly secured by opposing V-shaped clamps 48 which are bound together with heavy bolts 50. Insulating sleeves insulate these bolts 50 from the upper core segment. The channel iron-V-clamp-bolt assembly is identical to the that described with reference to the lower frame construction 18.

The upper frame construction 36 is supported on the lower frame construction 18 by four linearly telescoping jacks or tube guides 54, 56, 58 and 60. These jacks. mounted in pairs at opposite ends of the inductor 10, provide means for variably, adjustibly changing the size of the gap and for rigidly aligning the upper core segment 12, the lower core segment 14, and the electrical windings l6 irrespective of random horizontal and vertical motion and vibration experienced by inductor l0 during transport over rough terrain. This feature permits the inductor if) to be transported to and operated in remote field locations since the motion resulting from transport does not adversely affect the apparatus. Additionally, the inductor need not be precisely leveled since these jacks maintain the core segment-winding alignment even when the automotive test van carrying the inductor is parked on an incline. Furthermore, the jack construction permits the entire upper frame con struction 36 to be reciprocated with respect to the lower frame construction. The upper core segment is not reciprocally suspended from an integral, rigid frame of one-piece construction. Therefore, no more vertical space than is required to achieve the desired gap size is needed to house themobile inductor of the present invention. The housing space required is not dictated by fixed dimensions of a support frame. Consequently, this inductor may be transported in a light utility vehicle where headroom is limited such as the test van 4 illustrated in FIG. ll.

One of these linearly telescoping jacks, representative of the others, is illustrated in detail in FIG. 6. As shown, the jack 54 is mounted on special support plates, 62 and 64 which are secured to the bottoms of the upper frame channel irons 40 and 42 and the lower frame channel irons and 22 respectively with heavy bolts 66. Relatively thick jack mounting plates 68 are welded to each of the supporting plates 62 and 64, between the channel irons.

The jack 54 is comprised ofa rigid inner tubular body 70 which may be a hollow cylindrical or box beam. The bottom end of this inner tubular body 70 is force fitted and welded in an appropriate size hole in the thick mounting plate 68 mounted on the lower support plate 64, as shown at 72 in FIG. 6. The jack 54 further includes a rigid outer tubular body 74 telescoped down over the inner body 70 which is carried therein. The top of the outer tubular body 74 is similarly force fitted and welded in an appropriate sized hole in the upper supporting plate 62, and the mounting plate 68 carried thereon as shown at 76. The jack inner and outer bodies 70 and 74 respectively are held in spaced relation by packing in the form of a pair of collars 73 and 80 which are made ofa high density material having a slippery surface. In practice, high density polyethylene sold under the trademark Pactene has been found satisfactory. The first collar 78 is secured to the exterior of the inner bodys top and slides on the interior of the outer body 74. The second collar 80 is secured at the outer bodys lower end in a retaining cap 82 which is in turn secured to the outer body with at least one set screw 84. These collars prevent relative horizontal movement of the inner and outer bodies 70 and 74 and, hence, provide the jacks resistance to transverse movement.

The linearly telescoping jack 54 further includes a non-rotating feed member in the form of a plug 84, having an internal threaded bore, securely mounted in the top of the inner tubular body 70. A rotating feed screw 86 is operatively engaged with the feed member 84 and is mounted in fixed vertical relation to the outer tubular body. The feed screw 86 and the feed member may advantageously be provided with low friction, mating acme threads designed to withstand the high vertical stress characteristic of the present arrangement.

FIG. 7 illustrates in detail the arrangement for coupling the feed screw 86 to the upper frame construction. A stepped sleeve 88 is attached to the upper end of this feed screw 86 with a transverse pin 90. A hearing housing 92 is mounted to cap the hole in the upper thick jack mounting plate 68 and provides a bearing race. An antifriction bearing 94 is fitted over the stepped sleeve 88 to engage the sleeve and mate with the bearing race in the housing 92.

A cover plate 96 is mounted atop the upper frame construction 36 in which a second similar bearing arrangement is provided. A second stepped sleeve 98 is mounted at the upper end of the feed screw 86. A bear ing housing 100 caps the hole in the cover plate 96 through which the screw extends and provides a race for an antifriction bearinb 102 mounted on the second stepped sleeve 98. Thus the feed screw 86 may be freely rotated within the upper frame construction. When rotated, the feed screw 86 reciprocally separates the bearings 94 and 102 from the feed member 84. Thus, the linearly telescoping jack 54 may be reciprocally vertically extended to variably change the size of the gap g between the core segments 12 and 14.

As shown in FIG. 4 each feed screw in each jack is provided with an identical sprocket 104 mounted above the cover plate 96. These sprockets 104 are connected by a chain I06. An electrical driving motor 1108 is operatively coupled to the chain 106 whereby the feed screw in each linearly telescoped jack may be synchronously rotated so that the length of all jacks may be simultaneously, equally increased or decreased.

A suitable means for coupling the chain 106 to the motor 108 is shown in FIG. 5. The motor shaft 110 is provided with a small pulley 112 adapted to drive a larger pulley 114 to desirably reduce the driving rate of rotation of the motor. The large pulley 114 in turn drives a mated pair of bevel gears 116 and 118 which drive a final sprocket I20 connected to the chain 106. These pulleys and gears are mounted on shafts 122 rotatably positioned in a frame 124 mounted on the top of the cover plate 96. Other appropriate coupling arrangements and other means for synchronously driving the feed screws in the linearly telescoping jacks may be used.

Although a specific embodiment of the invention has, been disclosed in detail above, it is to be understood that this is for purposes of illustration. This disclosure is not to be construed as limiting the scope of the invention. since the described apparatus may be changed in details by those skilled in the art in order to adapt this mobile high reactive power inductor to special applicatrons.

I claim:

l. A mobile, accurately mechanically variable high reactive power inductor of the type having a magnetic core and an electrical winding magnetically coupled to the core, the magnetic core being in the form of upper and lower separable core segments separated by a gap, said high reactive power inductor being compact and suitable for transport on a utility vehicle such as a truck, railroad car or the like to a remote field location for testing large capacitive loads such as large capacitors, a group of capacitors, high voltage electrical power transmission lines, and the like, said mobile high reactive power inductor comprising:

rigid lower frame means for supporting the lower core segment and the electrical winding magnetically coupled to the core,

rigid upper frame means reciprocally mounted with respect to said lower frame means for supporting said upper core segment, the upper core segment thus being aligned with the lower core segment and the electrical winding and being vertically movably suspended above the lower core segment,

linearly telescoping jack means associated with said upper and lower frame means for vertically reciprocally positioning said upper frame means above said lower frame means and, hence, for vertically reciprocally positioning the upper core segment above the lower core segment to control the gap size between the upper and lower core segments, said linearly telescoping jack means including a plurality of spaced jacks mounted between said upper frame means and said lower frame means, each jack comprising:

a rigid outer tubular body;

a rigid inner tubular body slidably, reciprocally mounted within said outer tubular body for telescoping movement into and out of said outer tubular body;

packing means associated with said inner and outer tubular bodies for preventing relative horizontal movement thereof,

jack extension means for variably adjustably moving said inner tubular body out of and into said outer tubular body in telescoping fashion to variably, adjustably increase and decrease the total length of said jack,

for rigidly maintaining the alignment of the upper and lower core segments and the electrical winding magnetically coupled to the segments throughout the vertical range of travel of said telescoping jack means irrespective of vibration and other generally random horizontal and vertical motion which said high reactive power inductor may experience during field transport, and

means for driving said linearly telescoping jack means to reciprocally move said upper frame means and said lower frame means to adjust the gap size between the upper and lower core seg ments whereby said high reactive power inductor may be operated upon a vehicle while the core segments and electrical winding are maintained in aligned relation.

2. The mobile, accurately mechanically variable high reactive power inductor as claimed in claim I, wherein said packing means comprises:

a first upper collar mounted in encompassing relation about the outer periphery of said inner tubular body at said bodys top, said first collar slidably abutting the interior of said outer tubular body, and

a second lower collar mounted about the interior of said outer tubular body at said bodys bottom, said second collar slidably abutting the exterior of said inner tubular body, whereby said upper and lower collars hold said tubular bodies in transverse spaced relation and prevent relative transverse movement of said bodies.

3. The mobile, accurately mechanically variable high reactive power inductor as claimed in claim 1 wherein said jack extension means comprises:

a non-rotating low friction feed member fixedly mounted at the top of said inner tubular body, and

a rotating feed screw mounted in fixed vertical relation to said outer tubular body, said feed screw having threads which operatively engage said nonrotating feed member whereby rotation of said feed screw varies the relative vertical position of said inner and outer tubular bodies and, hence, varies the total length of said jack.

4. The mobile, accurately mechanically variable high reactive power inductor as claimed in claim 3, wherein said means for driving said linearly telescoping jack means is adapted to drive the rotating feed members in each of said jacks in synchronous rotation for simultaneously, equally increasing or decreasing the total length of each of said jacks to variably adjust the gap size between the upper and lower core segments.

5. The mobile, accurately mechanically variable high reactive power inductor as claimed-in claim 1 wherein there are at least three of said jacks extending between said upper and said lower frame means in generally parallel relation, mounted at noncolinear points to brace, and to thereby prevent relative horizontal movement of said upper and lower frame means and the upper and lower core segments. 

1. A mobile, accurately mechanically variable high reactive power inductor of the type having a magnetic core and an electrical winding magnetically coupled to the core, the magnetic core being in the form of upper and lower separable core segments separated by a gap, said high reactive power inductor being compact and suitable for transport on a utility vehicle such as a truck, railroad car or the like to a remote field location for testing large capacitive loads such as large capacitors, a group of capacitors, high voltage electrical power transmission lines, and the like, said mobile high reactive power inductor comprising: rigid lower frame means for supporting the lower core segment and the electrical winding magnetically coupled to the core, rigid upper frame means reciprocally mounted with respect to said lower frame means for supporting said upper core segment, the upper core segment thus being aligned with the lower core segment and the electrical winding and being vertically movably suspended above the lower core segment, linearly telescoping jack means associated with said upper and lower frame means for vertically reciprocally positioning said upper frame means above said lower frame means and, hence, for vertically reciprocally positioning the upper core segment above the lower core segment to control the gap size between the upper and lower core segments, said linearly telescoping jack means including a plurality of spaced jacks mounted between said upper frame means and said lower frame means, each jack comprising: a rigid outer tubular body; a rigid inner tubular body slidably, reciprocally mounted within said outer tubular body for telescoping movement into and out of said outer tubular body; packing means associated with said inner and outer tubular bodies for preventing relative horizontal movement thereof, jack extension means for variably adjustably moving said inner tubular body out of and into said outer tubular body in telescoping fashion to variably, adjustably increase and decrease the total length of said jack, for rigidly maintaining the alignment of the upper and lower core segments and the electrical winding magnetically coupled to the segments throughout the vertical range of travel of said telescoping jack means irrespective of vibration and other generally random horizontal and vertical motion which said high reactive power inductor may experience during field transport, and means for driving said linearly telescoping jack means to reciprocally move said upper frame means and said lower frame means to adjust the gap size between the upper and lower core segments whereby said high reactive power inductor may be operated upon a vehicle while the core segments and electrical winding are maintained in aligned relation.
 2. The mobiLe, accurately mechanically variable high reactive power inductor as claimed in claim 1, wherein said packing means comprises: a first upper collar mounted in encompassing relation about the outer periphery of said inner tubular body at said body''s top, said first collar slidably abutting the interior of said outer tubular body, and a second lower collar mounted about the interior of said outer tubular body at said body''s bottom, said second collar slidably abutting the exterior of said inner tubular body, whereby said upper and lower collars hold said tubular bodies in transverse spaced relation and prevent relative transverse movement of said bodies.
 3. The mobile, accurately mechanically variable high reactive power inductor as claimed in claim 1 wherein said jack extension means comprises: a non-rotating low friction feed member fixedly mounted at the top of said inner tubular body, and a rotating feed screw mounted in fixed vertical relation to said outer tubular body, said feed screw having threads which operatively engage said non-rotating feed member whereby rotation of said feed screw varies the relative vertical position of said inner and outer tubular bodies and, hence, varies the total length of said jack.
 4. The mobile, accurately mechanically variable high reactive power inductor as claimed in claim 3, wherein said means for driving said linearly telescoping jack means is adapted to drive the rotating feed members in each of said jacks in synchronous rotation for simultaneously, equally increasing or decreasing the total length of each of said jacks to variably adjust the gap size between the upper and lower core segments.
 5. The mobile, accurately mechanically variable high reactive power inductor as claimed in claim 1 wherein there are at least three of said jacks extending between said upper and said lower frame means in generally parallel relation, mounted at noncolinear points to brace, and to thereby prevent relative horizontal movement of said upper and lower frame means and the upper and lower core segments. 